View file public/assets/css/bootstrap-tags.css

.form-control-focus {
    color: #212529;
    background-color: #fff;
    border-color: rgba(13, 110, 253, .5);
    outline: 0;
    box-shadow: 0 0 0 0.25rem rgba(13, 110, 253, .25);
}
.was-validated :valid + .form-control-focus {
    border-color: #198754;
    box-shadow: 0 0 0 0.25rem rgba(25, 135, 84, .25);
}
.was-validated :invalid + .form-control-focus {
    border-color: #dc3545;
    box-shadow: 0 0 0 0.25rem rgba(220, 53, 69, .25);
}